That's a very difficult question to answer without more details. Are you buying, selling, simply valuing, where are you located, are the engines in good mechanical condition? Neither of the engines pictured are particularly valuable of collectable. With items like these, cost (or value) can only be determined by the current market, the method of sale and what someone is wiling to pay.

Cost? New or Used? Bernie @ cox international has them in a close approximation of each $35 to $60 in a new configuration. Used and abused in as shown condition I looked to e bay previous sales and your looking at $15 to $20 plus shipping.